The application of nanosecond-pulsed laser welding technology in MEMS packaging with a shadow mask
The application of nanosecond-pulsed laser welding technology in MEMS packaging with a shadow mask
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DOI：
10.1016/s0924-4247(01)00849-4
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发表时间：
2002-04
影响因子：
4.6
通讯作者：
C. Luo;Liwei Lin
中科院分区：
文献类型：
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作者：
C. Luo;Liwei Lin
用于 MEMS 封装应用的带有荫罩的纳秒脉冲激光键合工艺已得到成功演示。采用脉冲持续时间为 4-6ns、波长为 355nm、焦点直径为 1mm 的 YAG Surelit II 激光器，为采用 4μm 厚的铟层作为键合材料的玻璃与硅键合提供键合能量。当激光能量在8到22mJ之间并且使用多次激光照射时，通过实验找到了最佳键合参数。此外，具有预定义图案的普通白纸已成功用作掩模材料，以实现选择性加热和粘合。仿真结果表明，利用纳秒激光可以实现局部加热。施加激光功率后一微秒，铟/硅界面处的温度从 2500°C 降至 760°C，并在 1ms 后进一步降至 43°C。这种纳秒激光功率被认为可以为 MEMS 的局部加热和粘合应用提供合适的能量和时间。
A nanosecond-pulsed laser bonding process with a shadow mask for MEMS packaging applications has been successfully demonstrated. YAG Surelit II laser with pulse duration of 4–6ns, a wavelength of 355nm and a focal diameter of 1mm is used to provide the bonding energy for glass-to-silicon bonding using a 4μm thick indium layer as the bonding material. The optimal bonding parameters are found experimentally when the laser energy is between 8 and 22mJ and multiple laser shots are used. Furthermore, a regular white paper with pre-defined patterns has been successfully used as the masking material to achieve selective heating and bonding. Simulation results show that localized heating can be achieved by using the nanosecond laser. One micro-second after the laser power is applied, the temperature at the indium/silicon interface drops from 2500 to 760°C and drops further to 43°C after 1ms. This nanosecond laser power is believed to provide suitable energy and time for localized heating and bonding applications for MEMS.